A. Alev Karagözler

Adnan Menderes University, Güsel Hissar, Aydın, Turkey

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Publications (8)18.1 Total impact

  • Murat Uygun, A Alev Karagözler, Adil Denizli
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    ABSTRACT: Molecularly imprinted PHEMAH cryogels were synthesized and used for purification of carbonic anhydrase from bovine erythrocyte. Cryogels were prepared with free radical cryopolymerization of 2-hydroxyethyl methacrylate and methacryloylamido histidine and characterized by swelling degree, macroporosity, FTIR, SEM, surface area and elemental analysis. Maximum carbonic anhydrase adsorption of molecularly imprinted PHEMAH cryogel was found to be 3.16 mg/g. Selectivity of the molecularly imprinted cryogel was investigated using albumin, hemoglobin, IgG, γ-globulin, and lysozyme as competitor proteins and selectivity ratios were found to be 15.26, 60.05, 21.88, 17.61, and 17.42, respectively. Carbonic anhydrase purity was demonstrated by SDS-PAGE and zymogram results.
    Artificial cells, nanomedicine, and biotechnology (Print). 02/2014;
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    ABSTRACT: N-Methacryloyl-l-phenylalanine (MAPA) containing poly(2-hydroxyethylmethacrylate) based magnetic [mag-poly(HEMA–MAPA)] nanobeads was prepared for lysozyme purification form chicken egg white. MAPA was synthesized by reacting methacryloyl chloride with l-phenylalanine methyl ester and provided hydrophobic functionality to the nanobeads. Size of mag-poly(HEMA–MAPA) nanobeads was 386 nm and obtained by surfactant free emulsion polymerization of HEMA and MAPA having a specific surface area of 580 m2/g. Mag-poly(HEMA–MAPA) nanobeads were characterized by FTIR, AFM, TEM, ESR, and elemental analysis. Lysozyme adsorption experiments were investigated under different conditions in batch system (i.e., medium pH, protein concentration, temperature, salt type). Lysozyme adsorption capacity of mag-poly(HEMA) and mag-poly(HEMA–MAPA) nanobeads from aqueous solutions was estimated as 24 and 517 mg/g, respectively. Lysozyme molecules were desorbed with 50% ethylene glycol solution with 98% recovery. It was observed that mag-poly(HEMA–MAPA) nanobeads can be used without significant decrease in lysozyme adsorption capacity after ten adsorption–desorption cycles. Mag-poly(HEMA–MAPA) nanobeads was used for the purification of lysozyme from chicken egg white. Purity of lysozyme was estimated by SDS-PAGE.
    Materials Science and Engineering C 08/2009; 29(7):2165-2173. · 2.74 Impact Factor
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    ABSTRACT: Linoleic acid attached chitosan beads [poly(LA-Ch)] (1.25 microm in diameter) are obtained by the formation of amide linkages between linoleic acid and chitosan. Poly(LA-Ch) beads are characterized by FTIR, TEM, and swelling studies. Poly(LA-Ch) beads are used for the purification of immunoglobulin-G (IgG) from human plasma in a batch system. The maximum IgG adsorption is observed at pH 7.0 for HEPES buffer. IgG adsorption onto the plain chitosan beads is found to be negligible. Adsorption values up to 136.7 mg/g from aqueous solutions are obtained by poly(LA-Ch) beads. IgG adsorption saw an increase as a result of increasing temperature. Higher amounts of IgG are adsorbed from human plasma (up to 390 mg/g) with a purity of 92%. The adsorption phenomena appeared to follow a typical Langmuir isotherm. It is observed that IgG could be repeatedly adsorbed and desorbed without significant loss when we take into account the adsorption amount. It is concluded that the poly(LA-Ch) beads allowed one-step purification of IgG from human plasma.
    Colloids and surfaces B: Biointerfaces 02/2009; 70(2):266-70. · 4.28 Impact Factor
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    ABSTRACT: Dorystoechas hastata (D. hastata) is a monotypic plant endemic to Antalya province of Turkey. D. hastata leaves are used to make a tea locally called “çalba tea”. Diethyl ether (E), ethanol (A), and water (W) were used for the sequential preparation of extracts from dried D. hastata leaves. A hot water extract (S) was also prepared by directly boiling the powdered plant in water. The antioxidant activities of the extracts were tested by ferric thiocyanate (FTC) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging methods. E extract exhibited the greatest antioxidant activity with FTC method, whereas S extract exhibited the lowest IC50 value (6.17 ± 0.53 μg/ml) for DPPH radical scavenging activity. Total phenolic contents of the extracts were estimated by Folin–Ciocalteu method and S extract was found to contain the highest amount (554.17 ± 20.83 mg GAE/g extract) of phenolics. Extract A contained highest flavonoid content and there was a inverse linear correlation (R2 = 0.926) between IC50 values for DPPH radical scavenging activity and flavonoid contents of all extracts. Reducing power of extracts increased in a concentration-dependent manner. S extract was found to possess higher reducing power than equivalent amount of ascorbic acid at 20 and 25 μg/ml concentrations. Linear correlation between reducing power and concentration of E, A, and W extracts (R2 > 0.95) was observed. A, W, and S extracts contained relatively high levels of proline. The results presented suggest that D. hastata may provide a natural source of antioxidants and proline.
    Food Chemistry 11/2008; · 3.26 Impact Factor
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    ABSTRACT: Poly(ethylene glycol dimethacrylate-n-vinyl imidazole) [poly(EGDMA-VIM)] beads (average diameter 150–200 μm) was prepared by copolymerizing ethylene glycol dimethacrylate (EGDMA) with n-vinyl imidazole (VIM). Average pore size of poly(EGDMA-VIM) beads was 550 nm. The copolymer beads composition was characterized by elemental analysis and found to contain five EGDMA monomer units each VIM monomer unit. Poly(EGDMA-VIM) beads had a specific surface area of 59.8 m2/g. Poly-(EGDMA-VIM) beads were characterized by swelling studies and SEM. Cu2+ ions were chelated on the poly(EGDMA-VIM) beads, then these beads were used in the adsorption of uricase from Porcine Liver in batch system. The maximum uricase adsorption capacity of the poly(EGDMA-VIM)-Cu2+ beads was observed as 118.3 mg/g at pH 6.0. The Km values for immobilized uricase (poly(EGDMA-VIM)-Cu2+) (91.95 × 10−3 mM) was higher than that of free enzyme (7.5 × 10−3 mM). Vmax was calculated as 0.012 μmol/min mg protein for the free enzyme. For the immobilized enzyme, Vmax was calculated as 1.44 μmol/min mg protein. Free enzyme lose all of original activity in 35 days. On the other hand immobilized enzyme preserved 80% of original activity in same time. Storage stability was found to increase with immobilization. It was observed that enzyme could be repeatedly adsorbed and desorbed without significant loss in adsorption capacity or enzyme activity.
    Journal of Molecular Catalysis B Enzymatic 03/2008; 51:36-41. · 2.75 Impact Factor
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    ABSTRACT: The aim of this study was to examine occupation-associated effects on blood cytokine and immunoglobulin g (IgG) levels, antioxidant enzyme activities (SOD, GSHPx, and catalase), nitrite and nitrate levels, and malondialdehyde (MDA) concentrations in gas station workers (GSWs). Trace elements (Cu, Zn, and Pb) in serum, and the amount of hemoglobin in erythrocytes were also determined. Forty male GSWs and 30 male controls were included in the study. No significant difference was observed between the hemoglobin levels of GSWs and those in controls. Proinflammatory cytokine levels, such as tumor necrosis factor-α and interleukin-8 were significantly increased in GSWs’ sera. Interleukin-1β and interleukin-6 were below the detection limit of the assay in both the groups. Cytokine receptor interleukin 2R concentration and IgG levels were also significantly increased. Approximately, two-fold increase in nitrite and nitrate concentrations was found in GSWs’ sera. Erythrocyte antioxidant enzyme levels were significantly lower in GSWs’ blood. MDA concentration, a measure of lipid peroxidation, was found to be significantly elevated. Zn levels were significantly decreased, whereas Cu and Pb levels were increased in GSWs’ sera. Smoking was not found to be a major confounder for the association between exposure and blood parameters.
    Toxicological and Environmental Chemistry 10/2006; 88(4):587-594. · 0.72 Impact Factor
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    ABSTRACT: In this work, the protective effect of Vitamin E plus selenium (Vit E+Se) and melatonin against 7,12-dimethylbenz(a)anthracene (7,12-DMBA)-induced changes in superoxide dismutase (SOD), glutathione peroxidase (GSHPx), catalase (CAT) and carbonic anhydrase (CA) activities and malonedialdehyde (MDA) levels of mouse brain were compared. 12-month old mice were divided into four groups each including 10 animals. The first group served as control group. The second group was treated with 7,12-DMBA (20 mg/(kg day)). The third group was treated with 7,12-DMBA and Vitamin E (90 microg/(individual day)) and selenium (1.8 microg/(individual day)) simultaneously. The fourth group was treated with 7,12-DMBA and melatonin (4.2 mg/(kg day)) simultaneously. Treatment continued for 21 days after which the mice were sacrificed and brain homogenates were prepared. 7,12-DMBA treated group exhibited significantly decreased levels of brain SOD, GSHPx, CAT and CA activities and increased MDA levels as compared to control. Vitamin E+Se fully or partially restored enzyme inhibition except for SOD. Lipid peroxidation was also reduced in Vitamin E+Se treated group. Melatonin provided a better protection for SOD, GSHPx and CAT, and a plausible protection for CA activity. Protection against lipid peroxidation measured as MDA in melatonin treated group was appreciable although slightly lesser than the protection provided by Vitamin E+Se. The results imply that Vitamin E+Se and melatonin both provide chemoprevention against 7,12-DMBA-induced oxidative stress in mouse brain.
    Cancer Detection and Prevention 02/2005; 29(1):54-8. · 2.52 Impact Factor
  • A Alev Karagözler, Nihayet Mehmet, Kadir Batçioglu
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    ABSTRACT: The aim of this study was to examine solvent-associated effects on blood cytokine levels, antioxidant enzyme activities, and malondialdehyde (MDA) concentration in house painters. Trace element (Cu and Zn) and nitrite and nitrate levels as well as protein concentrations in erythrocytes and serum were determined. Thirty male house painters and 30 male clerical workers were included in the study. There were 13 smokers and 17 nonsmokers in each group. Hemoglobin concentrations were significantly lower in house-painter blood compared to controls. House painters had significantly higher concentrations of erythrocyte protein (excluding hemoglobin), whereas no significant difference was observed between serum protein levels. Proinflammatory cytokine levels, such as tumor necrosis factor-alpha and interleukin-8, were significantly increased in house painters' sera. Interleukin-6 was below the detection limit of the assay in both groups. Interleukin-1beta and cytokine receptor interleukin 2R concentrations were not significantly affected. Furthermore, a three- to fourfold increase in nitrite and nitrate concentrations was found in house painters' sera. Serum superoxide dismutase (SOD) and glutathione peroxidase (GSHPx) activities were significantly lower in house painters compared to controls. Malondialdehyde (MDA) concentration, a measure of lipid peroxidation, was found to be significantly elevated. In house painters, erythrocyte carbonic anhydrase and catalase activities were elevated approximately 11- fold and 2-fold, respectively. Zinc levels were significantly decreased in house painters' sera. Smoking was not found to be a major confounder for the association between solvent exposure and blood parameters.
    Journal of Toxicology and Environmental Health Part A 10/2002; 65(17):1237-46. · 1.83 Impact Factor